The question is, do you see the button anywhere else other than Samsung internet? If no, my solution is to use another browsed. If yes,, it is in your accessibility options, which have different settings for different phones/devices as described. If just in Samsung internet read the following solution https://us.community.samsung.com/t5/Android-12/Accessability-floating-button/m-p/2101612
If it is showing elsewhere then the most like option is in Accessability options. As mentioned above pull down from the top of your screen, find the symbol that looks like a gear wheel, click on that and search for 'Accessability options'. This is where it gets difficult. Different devices show different options. Look at my first answer directing you to variou solutions.
Thanks for the detailed reply...i have also read the link, but unfortunately my accessibility menu in the phone settings doesn't show an option for disabling any accessibility button! Also as you mentioned, the samsung browser(which I much prefer) also shows nothing in its setting related to an accessibility button either. It's so frustrating!
